The 1947 Wisconsin earthquake took place on May 6, immediately south of

Milwaukee Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee ...

at 15:25 (CST). It was the largest tremor to be historically documented in Wisconsin, but was not recorded by

seismographs A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The outpu ...

History

The area had been previously shaken by the

1909 Wabash River earthquake The 1909 Wabash River earthquake occurred at 04:45 local time on September 27 with a maximum Mercalli intensity of VII (''Very strong''). It measured 5.1 on a seismic scale that is based on an isoseismal map or the event's felt area. With moderate ...

, causing damage assessed at VII (''Very strong'') on the

Modified Mercalli scale The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the eff ...

across the Wisconsin-Illinois border. Two earthquakes were also reported in the state in 1912. Shocks in 1919 and 1925, the first from Missouri and the latter from Canada, occurred over enormous zones and affected the entire region, though not seriously. Earthquakes struck Wisconsin again in 1937 and 1939.

Damage

The area hardest hit was a strip of land in southeastern Wisconsin, while the earthquake was felt over a much more extensive wide area stretching across the Wisconsin-Illinois border, and to Lake Michigan and Waukesha. Damage consisted of broken windows and fallen

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, pots and dishes. The locals' initial impression was that an explosion had taken place. Many evacuated buildings into the streets. Corporate office buildings were emptied of workers. Numerous calls were made local fire departments, police stations and newspapers. Three reports were made to the

Milwaukee Fire Department The Milwaukee Fire Department provides fire protection and emergency medical services to the city of Milwaukee, Wisconsin. The department is responsible for an area of with a population of 594,833. It is the largest fire department in the Stat ...

, all describing explosions. Often described as "sharp", this was the most powerful earthquake to date in Wisconsin's seismological history. The earthquake broke a seismograph at

Marquette University Marquette University () is a private Jesuit research university in Milwaukee, Wisconsin. Established by the Society of Jesus as Marquette College on August 28, 1881, it was founded by John Martin Henni, the first Bishop of the diocese of M ...

. Many hotels, such as the Schroeder Hotel in Milwaukee, were rocked by the tremor. However, the earthquake caused no serious damage or casualties.

History

Damage

See also

References

Further reading